Multistage evaporator construction



@mta. 19% w. R. WILLIAMSON 392319334 MULTISTAGE EVAPORATOR CONSTRUCTION Filed March 17, l965 5 Sheets-Sheet 1 /NVENTOK Fig 3 I W/Ll/AM ROGER mummy/v 5 Sheets-Sheet 2 1196 w. R. WILLIAMSON MULTISTAGE EVAPORATOR CONSTRUCTION Filed March 17, 1965 lNVE/VTOK mm mm R,

W/LL MM ROGER W/LUAMS'O/V Get. 25, 1966 w. R. WILLIAMSON 3,21,334

MULTISTAGE EVAPORATOR CONSTRUCTION Filed March 17, 1965 5 Sheets-Sheet 5 A 7'7'ORNEY United States Patent 3,281,334 MULTISTAGE EVAPORATOR CONSTRUCTION William R. Williamson, Waterford, Conn., assignor to American Machine & Foundry Company, a corporation of New Jersey Filed Mar. 17, 1965, Ser. No. 440,539 Claims priority, application Great Britain, Mar. 23, 1964, 12,181/ 64 11 Claims. (Cl. 202-173) This invention relates in general to distillation apparatus, and, more particularly, to a modular construction of a multistage flash distillation apparatus.

An object of this invention is to provide an inexpensive modular unit which may be assembled into a low to moderate capacity as well as a high capacity flash distillation apparatus.

Another object of this invention is to provide a multistage distillation apparatus in which the sealing problem between stages is greatly simplified.

A further object of this invention is to provide a multistage distillation apparatus having mechanically stacked flash chambers which can be assembled together to provide a unit of any desired capacity.

Many other objects, advantages and features of invention reside in the particular construction, combination and arrangement of parts involved in the embodiment of this invention and its practice as will be understood from the following description and accompanying drawing wherein:

FIGURE 1 is a transverse vertical section through a multistage evaporator assembled from units according to this invention;

FIGURE 2 is a longitudinal vertical section taken on line 2-2 of FIGURE 1;

FIGURE 3 is a horizontal section taken through a fragment of a multistage evaporator on line 3-3 of FIG- URE 1;

FIGURE 4 is a perspective view of a set of condensing coils removed from a unit of this invention;

FIGURE 5 is a perspective view of a flash evaporator unit according to this invention; and

FIGURE 6 is a trans-verse vertical section of an evaporator unit according to this invention.

Referring to the drawing in detail, FIGURES 1, 2 and 3 show the assembled units 10 which are joined together to form the multistage flash evaporator of this invention. Each unit 10 has a rear wall 11 from which there projects the outer circumferential wall 12. An inner wall 13 extends forward from rear wall 11 within the outer circumferential wall 12. Each inner wall 13 defines a flash evaporating chamber and the space between the inner wall 13 and the outer circumferential wall 12 defines a condensing chamber.

An opening 14 having the inwardly and downwardly extending lips 15 is formed in the inner wall 13 to provide a communication between the evaporating and condensing chambers. Each rear wall 11 contain-s an opening 16 through which heated liquid passes to flash into vapour in a subsequent evaporating chamber. Two deflectors 17 and 18 extend upward from the bottom of each inner wall 13 about an opening 16. The deflectors 17 and 18 extend forward from a rear wall 11 and are inclined toward each other. The deflectors 17 and 18 do not extend completely the length of a unit 10 to contact an adjacent wall 11. A curved baflle 19 extends forward from each rear wall 11 above the deflectors 17 and 18 below the opening 14.

Referring now to FIGURE 2, a first end plate 20 has outer and inner walls 12 and 13, deflectors 17 and 18, and a curved baflle 19 extending from it. The first end plate 20 is larger in diameter than the outer circumferential "ice walls 12. A second end plate 21 is a disc which is also larger in diameter than the outer circumferential walls 12. Tie bolts 22 extend between the first and second end plates beyond the outer circumferential walls 12 to hold together a number of the units 10 to form a distillation apparatus according to this invention.

To provide seals between the evaporating and condensing chambers of the units 10, gaskets 23 are placed in grooves in the edges of the outer circumferential walls 12. The gaskets 23, or any other suitable sealing means, form an air tight joint against a wall 11 of an adjacent unit 10. The inner wall 13 of each unit 10 butts against a gasket 24 which may be glued or otherwise secured to the wall 11 of an adjacent unit 10. The end of each curved bafie 19 also butts against a gasket 25 which provides a water tight seal against a wall 11. If desired, the endmost unit 10 adjacent to the second end plate 21 may have an outer circumferential wall 12 which does not contain a groove but butts against a flat gasket 26.

Sets of condensing coils 27 are disposed in each condensing chamber formed between outer and inner walls 12 and 13. Sets of condensing coils 27 each have two manifold-s 28 and 29 connected by a plurality of cooling coils 30. As shown in FIGURE 3, the manifolds 28 have flared ends 31 which extend through the rear walls 11. The projecting ends 32 of the manifolds 28 are sealed or closed. The manifolds 29 may be welded or otherwise fixed to project from a rear wall 11 and have their projecting ends 33 open to receive flow. Thus, when the units 10 are assembled, the open ends 33 of each manifold 29 extend into the flared ends 31 of an adjacent manifold 28. Any other desired means, such as welding or standard couplings, may be used to connect the manifolds 28 and 29.

Referring now to FIGURE 2, heated brine, or any other fluid to be evaporated, is introduced through pipe 36 into the evaporating chamber of the first unit 10 formed by the end plate 20 and the inner wall 13 projecting from it. The heated brine flashes into steam between the deflectors 17 and 18 below the baflle 19. The heated fluid, now slightly cooled, passes through the opening 16 into the next unit 10 to again flash into vapour. The heated brine continues to successively flash into vapour until it is withdrawn through pipe 37 which passes through the second end plate 21 to enter the endmost unit 10.

As liquid flashes into vapour, it passes through the openings 14 to condense about the sets 27 of coils 30. Condensate flows downwards within the outer circumferential walls 12 to collect in the bottom of each unit 10. This distillate then passes through the small apertures 38 formed in the rear walls 11 within the condensing chambers to be pumped from the apparatus through pipe 40 which extends through end plate 21. Cooling water enters through pipe 35 to pass successively through the sets of cooling coils 27 to be withdrawn through the pipe 42 extending through end plate 20.

The units 10 may be mechanically stacked in any desired number with their gaskets originally compressed by the tie bolts 22. In operation, the units 10 are further compressed by atmospheric pressure squeezing together the large diameter end plates 20 and 21 under the vacuum of operation. In small units having a capacity from to 2,000 gallons per day, four or more units 10 may be efficiently used which are only sixteen inches in diameter and four inches in length. This particular construction allows the use of relatively long condensing tubes 30 with a given size of evaporating chamber. Using this apparatus, it is possible to operate 1,000 gallons per day and smaller evaporators with temperature differences of less than two degrees F. between stages.

FIGURE 6 shows a one-stage unit 10' functionally similar to the unit 10 shown in FIGURE 1, but which is structurally modified to provide a simpler construction, easier assembly and better flow of control. For simplified understanding, the parts of the structure of FIGURE 6, corresponding to those in FIGURE 1, have been given the corresponding prime reference numeral.

The unit diflers from unit 10 of FIGURE 1 in that the lower portion of the circular cross section has been changed to comprise a flat bottom 40 and substantially vertical side walls 42 which join tangentially with an upper semi-circular portion 44. This cross section might be described as a modified D-shape lying on its side.

An advantage of this construction includes the ability to assemble the headers 28' and 29' of the heat exchangers in a self-supporting, interlocking and easily drainable manner. A second advantage lies in the fact that the flat bottom surface affords a greater area over which flash can take place. The opening 16 of FIGURE 1 can thus be modified into an elongated opening 16 shown in FIG- URE 6, lying along the bottom of the unit. Deflector means can be employed in conjunction with opening 16' which will direct the fluid upward to baffle 19'.

The units 10 of this invention may be made of cast aluminium with aluminium sets of tubes 27. The units 10 may also be made of plastic with metal condensing tubes 30. Since the intermediate stages are substantially identical, any desired number of stages may be arranged to give optimum efficiency and capacity in a given installation. Larger sizes of this invention could be fabricated from weldments which would be bolted or welded together. The units 10 of this invention may be eflectively employed in apparatus having capacities ranging from 100 to 2,000,000 gallons per day.

While this invention has been shown and described in the best form known, it will nevertheless be understood that this is purely exemplary and that modifications in the construction, arrangement and combination of parts may be made without departing from the spirit of the invention.

What is claimed is:

1. A multistage flash evaporator having a plurality of substantially identical vertically oriented units stacked horizontally together, each of said units having a rear wall, an outer wall extending forward from said rear wall, an inner wall extending forward from said rear wall, said inner wall defining an evaporating chamber and said inner and outer walls defining, between them, a condensing chamber surrounding said evaporating chamber, each said rear wall containing an opening in the bottom of said evaporating chamber, each said rear wall containing an aperture in the bottom of said condensing chamber, said inner wall containing an upper opening for the passage of vapours into said condensing chamber and condensing coils in said condensing chamber.

2. A multistage flash evaporator as claimed in claim 1, wherein a baflle is provided extending forward from said rear wall under the opening in said inner wall.

3. A multistage flash evaporator as claimed in claim 2, wherein said baflie curves downwardly.

4. A multistage flash evaporator as claimed in claim 2, wherein deflector plates are provided extending upward from said inner wall and forward from said rear wall on both sides of the opening in said rear wall, said deflector plates being located below said bafiie.

5. A multistage flash evaporator as claimed in claim 4, wherein said deflector plates are inwardly inclined.

6. A multistage flash evaporator as claimed in claim 1, wherein said inner and outer walls are substantially cylindrical.

7. A multistage flash evaporator as claimed in claim 1, wherein downwardly extending lips are provided about the opening in said inner wall.

8. A multistage flash evaporator as claimed in claim 1, in which the rearmost end plate extends beyond the outer wall of the rearmost of said units; a foreward end plate extending beyond the outer wall of the foremost of said units; sealing means disposed between said foreward end plate and the edges of said inner and outer walls of the foremost of said units and sealing means disposed between the edges of said inner and outer walls and the rear walls of adjacent units; and tie bolts extending between said rearmost and foreward end plates beyond said outer walls holding said units together, said cooling coils being arranged in sets.

9. A multistage flash evaporator as claimed in claim 8, wherein each of said sets of cooling coils comprises two manifolds extending longitudinally within said condensing chamber, and coils extending between said manifolds substantially about said inner wall within said condensing chamber.

10. A multistage flash evaporator as claimed in claim 9, wherein one of said manifolds in each of said condensing chambers is connected to a manifold in a forwardly disposed adjacent condensing chamber and the other of said manifolds is connected to a manifold in a rearwardly disposed adjacent condensing chamber.

11. A multistage flash evaporator as claimed in claim 10, wherein each of said rear walls has one of said manifolds extending through it.

References Cited by the Examiner UNITED STATES PATENTS 2,944,599 7/1960 Frankel 159-2 3,172,824 3/1965 Mulford 202-173 3,180,805 4/1965 Chirico 159-2 X 3,192,131 6/1965 Loebel et al 159-2 X 3,197,387 5/1965 Lawrence 159-2 X 3,213,000 10/1965 Ewing l592 X NORMAN YUDKOFF, Primary Examiner. J. SOFER, Assistant Examiner. 

1. A MULTISTAGE FLASH EVAPORATOR HAVING A PLURALITY OF SUBSTANTIALLY INDENTICAL VERTICALLY ORIENTED UNITS STACKED HORIZONTALLY TOGETHER, EACH OF SAID UNITS HAVING A REAR WALL, AN OUTER WALL EXTENDING FORWARD FROM SAID REAR WALL, AN INNER WALL EXTENDING FORWARD FROM SAID REAR WALL, SAID INNER WALL DEFINING AN EVAPORATING CHAMBER AND SAID INNER AND OUTER WALLS DEFINING, BETWEEN THEM, A CONDENSING CHAMBER SURROUNDING SAID EVAPORATING CHAMBER, EACH SAID 